Which list contains only rational numbers?

Answer: Option A.
Step-by-step explanation:
Rationals numbers are defined as all those numbers which can be written as fractions, which have the form:
[tex]\frac{a}{b}[/tex]
Being the numerator a and the denominator b integer numbers.
The numbers in the option A are rational numbers, because:
[tex]-4=\frac{-4}{1}\\\\0=\frac{0}{1}\\\\\frac{1}{4}\\\\\sqrt{\frac{9}{4}}=\frac{3}{2}[/tex]
All these number can be written as fractions, therefore all of them are rational numbers.